She told the Thanks A Million With Angela Scanlon podcast that models are “constantly being compared” to others working in the industry.
The Irish actress, who previously worked as a model, said that while modelling can be an “incredible education” that “opens so many doors”, it also “infantilises you and it stunts you in so many other ways”.
Balfe added: “You’re supposed to automatically be this fun, interesting, edgy person that fashion people want to be around.
“But then at the same time you have to be so skinny and androgynous.”
She added you are “constantly being compared to people” and there are “always people doing better”.
“I think, as a young woman in your teens and twenties, it’s hard enough.
“You know, there’s so many times where you would go into castings or even fittings for jobs that you already supposedly had and somebody in the room would just be annihilating how you look, or your lack of personality, or you talk too much.
“All in front of you. It’s really tough. I have so much admiration for girls who can come through that unscathed.”
She said that models are constantly being judged by others working in the industry.
“The worst thing, I think, if you talk to any model, used to be the days you’d have to go into the agency and you walk in and literally everybody is scanning you head to toe,” she said.
“What are you wearing? Do you look cool? Are you thin enough? Are you going to the right places or dating the right people?”
Balfe added she was “very lucky” during her time working as a model and she worked with “some amazing bookers and had some amazing agencies”.